Ballistic armor

ABSTRACT

According to an embodiment, a ballistic structure comprises a front pellet layer configured to face a ballistic threat and rear pellet layer therebehind, each of the pellet layers comprising a plurality of pellets, which can be made of a ceramic material, having cylindrical bodies with their height axes in both layers being substantially parallel to each other, the pellets being arranged in a honeycomb pattern within a binder matrix, the pellet layers being codisposed such that all interior spaces (i.e., spaces which are surrounded on all sides by pellets) of each pellet layer are entirely overlapped by an area of the other pellet layer that is free of such spaces, the two layers being by an intermediate layer having such a width and being made of such a material as to allow the rear layer to rigidly support the front layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Israel Patent Application No. 210014 filed on 15 Dec. 2010, the contents of which are incorporated herein, in their entirety, by this reference.

TECHNICAL FIELD

Embodiments of the present invention are directed toward composite ballistic armor, and especially to armor comprising layers of pellets made of high density material, to provide protection against incoming projectiles, for use as stand-alone armor or as add-on armor.

BACKGROUND

Ballistic armor of the kind to which embodiments of the present invention refer is disclosed, for example, in WO 2010/053611, and it comprises two armor layers of ceramic spheres, held within a matrix of polymeric material in order to distribute kinetic energy and momentum from the impact of a projectile across a greater area.

IL 163183 discloses another armor which comprises a plurality of longitudinal members in a tightly packed array, wherein the members are mutually spaced apart from one another forming a continuous gap in the array.

U.S. Pat. No. 3,813,281 discloses a composite flexible armor comprising layers of rigid platelets separated by compressible foam material having gas cells therein. A high velocity projectile striking a platelet in one layer compresses and forces gas from the cells in the foam material to absorb and dissipate kinetic energy.

SUMMARY

According to one aspect of the presently disclosed subject matter, there is provided a ballistic structure comprising a front pellet layer configured to face a ballistic threat and rear pellet layer therebehind, each of the pellet layers comprising a plurality of pellets, which can be made of a ceramic material, having cylindrical bodies with their height axes in both layers being parallel to each other, the pellets being arranged in a honeycomb pattern within a binder matrix, the pellet layers being codisposed such that all interior spaces (i.e., spaces which are surrounded on all sides by pellets) of each pellet layer are entirely overlapped by an area of the other pellet layer that is free of such spaces, the two layers being by an intermediate layer having such a width and being made of such a material as to allow the rear layer to rigidly support the front layer.

Some of the pellets in each layer can be in contact with adjacent pellets of the same layer.

A majority of the pellets in each layer can be in contact with adjacent pellets of the same layer.

The pellets can comprise belts, so that each belt surrounds a corresponding pellet and configured for confinement thereof.

The belt member according to an embodiment of the present invention may be made of a variety of materials so long as the belt member possesses a minimal amount of tensile strength, which is at least about 3 kg/mm². Possible materials include, but are not limited to, metal alloys such as Aluminum, Titanium and Steel alloys, composites such as glass, carbon and aramids, Kevlar™, high strength plastics such as Nylon, polycarbonates, and polyamids, High Density Poly-Ethylene (HDPE) within various resins, carbon fibers and the like. The various resins may include simple fabric, winded fabrics, or mats reinforcement resins.

The intermediate layer is configured to provide structural confinement to the front and rear layers.

The binder matrix can be rigid or flexible, in which case the entire structure can be flexible.

The distance between the pellets of each layer can be no greater than 0.3 mm.

The front and rear pellet layers, and the intermediate layer can be formed within a single binder matrix, or each of the front and rear pellet layers can be within a binder matrix separate from that which the other of the layers is within.

The ballistic armor can be formed such that the distance between the front and rear layers does not exceed 0.15 times the diameter of each pellet.

Centers of pellets in each of the pellet layers can overlap with points of contacts of pellets in the other of the pellet layers.

Each of the layers can be offset, relative to the other of the layers, along a row thereof by a distance equal to one half of the diameter of one of the pellets.

The intermediate layer can be made of ballistic fabric or metal or the material of said binder matrix.

The cylindrical bodies of the pellets can each have parallel height axes and be of the same diameter.

The binder matrix can be made of a thermoplastic material.

The pellets of the front pellet layer can be of a higher hardness than the pellets of the rear pellet layer.

The pellets can be made from a material selected from the group consisting of alumina, silicon carbide, boron carbide, ultra high-hardness steel, and cemented carbide.

The pellets can be made of a transparent material constituting a transparent ballistic structure. For example, the pellets can be made of a materiel selected from the group consisting of transparent soda-lime, transparent borosilicate, transparent aluminum oxide, transparent magnesium aluminum oxide (SPINEL), transparent sapphire and transparent aluminum oxynitride (ALON).

The binder matrix, configured for both attaching the pellet one to the other and for attaching the layers one to the other, can be made of a transparent material. For example, the binder matrix can be made of a thermoset material selected from the group consisting of transparent polyurethane resin (PUR), transparent polyvinyl-butyral (PVB), phenoxy resin and phenolic resin, or of a thermoplastic material such as polycarbonates and polyamides.

The transparent ballistic structure can further comprise a backing layer made of materials selected from the group of a thermoset or a thermoplastic, as listed above. The material of the backing layer can be similar or different from that of the binder matrix.

According to another aspect of the presently disclosed subject matter, there is provided armor module comprising a ballistic structure as described above, and a casing, which can be rigid, enclosing the ballistic structure at least along sidewalls thereof extending between external surfaces of the module that are parallel to the pellet layers.

The casing can be made from a metal (such as aluminum), fiberglass, or Kevlar.

The armor module can further comprise at least one backing layer, which can comprise ballistic fabric. The ballistic fabric can be selected from the group consisting of aramid, fiberglass, and polyethylene.

The backing layer can comprise a hard layer, which can be made from a material selected from the group consisting of high-hardness steel, hard steel, aluminum, and titanium.

At least one sidewall of the casing can be formed with a projecting portion, wherein one of the front and rear pellet layers projects beyond the other and is accommodated within the projecting portion.

The height of the projecting portion can be substantially equal to that of the pellet layer accommodated therewithin.

The projecting portion can be formed such that its width is at least one half of the diameter of one of the pellets, and/or such that its width is no greater than three times the diameter of one of the pellets.

The ballistic structure can comprises semi-circular pellets disposed along edges of the front and rear pellet layers, wherein the edges are adjacent the sidewall formed with the projecting portion.

The armor module can be configured to defeat a WC projectile.

According to a further aspect of the presently disclosed subject matter, there is provided an armor assembly comprising a plurality of armor modules as describe above, wherein the modules are arranged such that projecting portions of adjacent modules overlap one another.

According to a still further aspect of the presently disclosed subject matter, there is provided a vehicle comprising a plurality of armor modules as described above.

According to a still further aspect of the presently disclosed subject matter, there is provided a vehicle comprising an armor assembly as described above.

According to a still further aspect of the presently disclosed subject matter, there is provided a vehicle comprising the transparent ballistic structure as described above.

One or more ballistic structures can constitute one or more windows of the vehicle.

One or more windows can be selected, for example, from the group consisting of side windows, back windows and turret windows.

According to a still further aspect of the presently disclosed subject matter, there is provided a flexible armor comprising a ballistic structure as described above, within a flexible enclosure.

The flexible armor can further comprise one or more flexible fabric layers between the rear pellet layer and the flexible enclosure.

The fabric layers can be sewn together and/or at least partially attached to each other by a flexible adhesive.

The flexible armor can further comprise at least one flexible hinge configured for bending the flexible armor between two adjacent rows thereof, which can facilitate bending of the flexible armor through 180°. The hinge can be made of a strip of flexible material attached to the two adjacent rows of each pellet layer. The hinges can be made of a fabric or elastomeric material, such as aramid, polyester, or rubber.

According to a still further aspect of the presently disclosed subject matter, there is provided a method for producing a ballistic structure as described above, the method comprising:

-   -   providing a front fabric layer and plurality of pellets;     -   arranging the front fabric layer in the form of a cavity having         a generally horizontal bottom and generally vertical side walls;     -   arranging some of the pellets in the cavity on the bottom to         form a front pellet layer;     -   arranging other of the pellets on top of the front pellet layer         to form a rear pellet layer; and     -   applying binder material to the pellets and the fabric layers in         such a way (for example by heating and/or applying pressure to         the binder matrix) so as to simultaneously form a matrix, which         constitutes with the pellets the ballistic structure, and to         bind the front layer thereto.

The method may further comprise introducing an intermediate layer between at least a portion of the front and rear pellet layers.

The method may further comprise providing a casing, wherein the front fabric layer is arranged within the casing.

The method may further comprise producing an armor module as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the presently disclosed subject matter and to see how it can be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

FIG. 1A is a schematic perspective view of a ballistic structure comprising two layers of pellets for use in a ballistic armor according to the presently disclosed subject matter;

FIG. 1B is a schematic plan view of the arrangement of pellets in the ballistic structure illustrated in FIG. 1A;

FIG. 1C is a schematic plan view of one layer of the ballistic structure illustrated in FIGS. 1A and 1B;

FIG. 1D is a schematic side view of the ballistic structure illustrated in FIGS. 1A and 1B, according to one example thereof;

FIGS. 1E and 1F are schematic perspective and plan views, respectively, of according to one modification of the ballistic armor according to the presently disclosed subject matter.

FIG. 2 is a schematic perspective view of a pellet of the ballistic structure illustrated in FIGS. 1A and 1B;

FIG. 3 is a schematic enlarged perspective view of a portion of the ballistic structure illustrated in FIGS. 1A and 1B, shown with a projectile impinging thereupon;

FIG. 4 is a schematic perspective view of a vehicle with add-on armor according to the presently disclosed subject matter;

FIG. 5 is a schematic cross-sectional view taken along line V-V is FIG. 4;

FIG. 6 is a schematic perspective view of a vehicle with standalone armor according to the presently disclosed subject matter;

FIG. 7A through 7C are alternative schematic cross-sectional views taken along line VII-VII is FIG. 6;

FIG. 8A is a schematic side cross-sectional view of an example of an armor module;

FIG. 8B is a schematic side view of an armor assembly made of several of the armor modules illustrated in FIG. 8A;

FIG. 8C is a schematic plan view of an arrangement of pellets within the armor module illustrated in FIG. 8A;

FIG. 9 is a schematic illustration of a person illustrating one placement of a body armor;

FIG. 10A is a schematic illustration of a body armor;

FIG. 10B is a schematic cross-sectional view of the armor illustrated in FIG. 10A;

FIGS. 10C is a schematic top view of a pellet layer of a the body armor illustrated in FIGS. 10A and 10B, according to a modification;

FIG. 10D is a schematic side view of the body armor illustrated in FIGS. 10A and 10B, according to the modification illustrated in FIG. 10C; and

FIGS. 11A through 11C illustrate a method of producing the ballistic structure illustrated in FIGS. 1A and 1B.

DETAILED DESCRIPTION OF EMBODIMENTS

As illustrated in FIGS. 1A and 1B, there is provided a ballistic structure, which is designated by 10. The structure 10 is shown as comprising two pellet layers 12 a, 12 b (collectively referred to by 12) of cylindrical pellets 14, which will be hereinafter referred to as front and rear pellet layers, respectively. In FIG. 1B the rear layer 12 b is shown in broken lines. It should be noted that the structure 10 can comprise more than two pellet layers, at least two of which (not necessarily its rear and front layers) are configured as the pellet layers 12 a and 12 b, as described herein.

As best seen in FIG. 2, each of the pellets 14 is formed with a cylindrical portion 16 having a circular cross-section of a diameter, which is the same for all the pellets in both layers 12. According to the example illustrated in FIG. 2, the cylindrical portion 16 constitutes the entire pellet 14 having flat (planar) front and rear ends 18 a, 18 b flat; however, it will be appreciated that the pellets can be formed with other features, such as domed ends on one or both ends. Such a structure can be as disclosed, for example, in the Applicant's IL 169230, or any other suitable structure.

The pellets 14 can be made of any high density material used in ballistic protection, for example, against small-arms fire such as ball-type and armor-piercing projectiles, such as ballistic ceramics. Preferably the material can be alumina, silicon carbide. However, other material can be used, for example, the boron carbide, ultra high-hardness steel (UHH), cemented carbide (hard metal), or any other suitable material. The materials of the pellets 14 of the two layers can be different from each other. In particular, the pellets 14 of the front pellet layer 12 a can be harder than those of the rear pellet layer 12 b. However, it will be appreciated that the reverse can be the case, and the pellets both layers 12 can be made of the same material. In addition, while each layer 12 typically comprises pellets 14 made of a single material, each can comprise pellets made of different materials.

The two layers 12 a and 12 b of the pellets 14 can be held together in one common binder matrix or can each comprise its own matrix and be assembled, so that the pellets heights define a common thickness of the two layers. In any case, the two layers are held and/or assembled so as that their movement relative to each other is prevented at least in the directions perpendicular to their thickness direction.

The material of the matrix can be any suitable solid or flexible adhesive material, including, but not limited to, a plastic adhesive, including thermosetting and thermoplastic materials, such as for example, polyurethane, polyester, and epoxy.

The pellets 14 can be made of a transparent material, such as glass, and held in a transparent binder matrix, to allow obtaining an essentially transparent ballistic armor structure for ballistic protection of those parts of armored vehicles where at least some amount of vision is required.

A transparent binder matrix, which can be made of a castable transparent polymer resin, can be used to adhere the pellets 14 to each other and to attach the armor to a surface to be protected, such as, for example, a window of a vehicle.

In case the ballistic structure 10 is further provided with an intermediate layer between the layers 12 a and 12 b, as will be further described with reference to FIG. 1D, the intermediate layer will also be made of a transparent material.

Each layer in the transparent ballistic structure as described above, can be produced, for example, in accordance with “Pellets-in-PUR (polyurethane resin)” concept, as described by Carton and Brooks in “Innovative Transparent Amour Concepts” (26^(th) International Symposium on Ballistics, Miami, Fla., Sep. 12-16, 2011).

The transparent ballistic armor further comprises a transparent backing layer, made of a material similar or different of that of the binder matrix.

The transparent ballistic structure can be a stand-alone product configured to replace an existing transparent surface.

Although the pellets of each layer are shown to be in contact with each other, it will be appreciated that this does not necessarily need to be the case.

The pellets 14 can be coated, e.g., with a material improving their adhesion to the matrix (such as for example the primer as disclosed in the Applicant's IL 169230) or to provide the pellets with some other desired properties.

Each pellet 14 can be formed as a core surrounded by a belt member 81 configured for confining the pellet and made of a rigid material different from that of the core.

The belt member 81 mounted on the pellets 14, as shown in FIGS. 1E and 1F. The belt member 81 is a thin-walled tube whose circular inner and outer perimeters conform to the shape of the pellet 14. Each belt member 81 surrounds one pellet 14 to form a single unit 83. The units 83 are arranged in each layer of the armor as described above, with the belt members being in direct contact with each other. Examples of possible forms of belt members are described in detail in the Applicant's EP 1363101 and their description, together with the description of the armor including such belt members, is incorporated herewith by reference.

It will be appreciated that in the above described arrangements, and other similar arrangement wherein the pellets 14 or the pellet units (each including a pellet and a belt member mounted thereon as described above) are designed to be in contact with adjacent pellets or pellet units, respectively, should be considered as ‘being in contact’ even though they are not in direct contact each with another, as an artifact of the manufacturing process.

The pellets are arranged to form a “honeycomb” pattern, wherein most of the pellets 14 (expect for those on the periphery) are surrounded by six adjacent pellets. As illustrated in FIG. 1C, when arranged in the “honeycomb” pattern, the pellets 14 form three sets 19, 20 and 21 of parallel rows 19 a, 19 b, . . . 19 n; 20 a, 20 b, . . . 20 n; and 21 a, 21 b, . . . 21 n, respectively, each of which defines with the rows of other sets an angle of 60°.

With reference to FIGS. 1B and 1C, the pellet layers 12 a and 12 b are codisposed such that, in the plan view of the ballistic structure, each layer is offset, relative to the other layer, along the rows of the set 20 thereof by a distance equal to that of half of the diameter of a pellet 14. It will be appreciated that the term “offset” when used herein the specification and claims refers to an arrangement of two identical layers, wherein one has been translated from a position wherein elements of each the layer lie in full registration with corresponding elements of the other.

With this arrangement, though the rows of set 20 of the rear layer are fully aligned with the rows of set 20 of the front layer, the pellets 14 in these rows in one of the layers are offset as described above, relative to the pellets 14 of these rows in the other layer, the rows of the sets 19 and 21 of the one of the layers being thus off-set relative to the corresponding rows of the other. Staggering the front and rear layers 12 a and 12 b as described above results in points of contact 24 between adjacent pellets 14 in the rows of the set 20 in one of the layers overlapping centers 26 of the pellets in the corresponding rows in the other layer (it will be appreciated that as in the plan-view depiction of FIG. 1B, the points of contact 24 are coincident with the centers 26, both reference numerals are directed toward the same point in the figure); whilst points of contact of the pellets 14 in the rows of each one of the sets 19, 21 in one of the layers overlap with the points of contact of the pellets in the rows in the other set 21, 19 of the other layer.

The above described arrangement ensures that all spaces 22 between adjacent pellets 14 of each pellet layer are overlapped by the area of the other layer that is free of such spaces.

As shown for example in FIG. 1D, the pellets of the layers 12 a and 12 b can be spaced by an optional intermediate layer 13 or by the material of the binder matrix. The intermediate layer can be constituted by one or several plies of a material different from the material of the pellets and of the binder matrix, e.g., a fabric material such as aramid or fiberglass, and/or by a metal layer such as aluminum.

The intermediate layer 13 can support the front and rear pellet layers 12 a, 12 b, for example by providing structural confinement. In addition, it can reduce shockwave propagation between the front and rear pellet layers 12 a, 12 b. With the thickness of the intermediate layer 13 being S (FIG. 1D), advantageous results have been obtained with 0<S≦0.3 D, in particular 0.1 D≦S≦0.3 D. With such thickness, the intermediate layer, on the one hand, provides close disposition of the two layers to one another allowing the rear layer 12 b to rigidly support the front layer 12 a, and on the other hand, can still provide the above structural confinement of the layers. It will be appreciated that the terminology “rigidly supporting”, when used herein the specification and claims (for example to describe the relationship between the rear armor layer 12 b vis-à-vis the front hard armor layer 12 a), indicates that any displacement of the supported layer toward the supporting layer resulting from the impact of a projectile is resisted by the supporting layer, or that the supporting layer is displaced in tandem therewith (however, due at least in part to the disposition of the pellets 14 in the different layers, the movement of pellets due to displacement of each of the layers 12 will differ from one another).

The ballistic structure 10 as described above can provide a high degree of ballistic protection, with a relatively low weight. For example, it can provide a degree of protection equal or similar to that provided by a similarly designed armor having a single layer of pellets, while having a weight per unit area which is about 80%-90% thereof. In particular, it has been surprisingly uncovered that, to provide the same degree of protection in an armor having such single layer of pellets, the pellets need to have a height greater than the total height the two layers described above.

In addition, the ballistic structure 10 can provide protection not available when a single layer of pellets is used. In such single layer structure, as illustrated in FIG. 3, an impinging projectile 28, which can be, e.g., of a ball-type or comprising a material that is harder than that from which the pellets are made, which strikes the ballistic structure 10 having spaces 22 between adjacent pellets 14 can at least partially penetrate the front pellet layer 12 a. For example, a WC (tungsten carbide) projectile, which is harder than some ceramics used to manufacture ballistic pellets, striking one of the spaces 22 of the front pellet layer 12 a, can penetrate and/or produce spall which would penetrate therethrough. In addition, a deformable lead-core projectile striking one of the spaces 22 of the front pellet layer 12 a can deform and penetrate the layer via the space. By providing the rear pellet layer 12 b positioned in relation to the front pellet layer 12 a as described above, penetrations, inter alia as described above, are fully protected against.

The ballistic structure 10 as described above with reference to FIGS. 1A through 3 is normally to be utilized as a part of an armor module which further comprises at least a backing layer, so that the structure 10 is directed to break or at least shatter incoming projectiles, whilst the backing layer is directed to stop its fragments from reaching a body to be protected. As will be described below, the armor module can further comprise at least one front layer made of a ballistic material, such as high-hardness steel or a ballistic fabric such as aramid, polyethylene, fiberglass, or any other suitable material. Alternatively or additionally, the module can comprise a wrapping made of a flexible material as listed above, or a rigid casing made for example of metal, which tightly holds all layers of the armor together.

It will further be appreciated that although the ballistic structure 10 is described above as comprising individual pellets 14, the pellet layers 12 may be constructed using various other structures which give rise to protected areas surrounded by spaces, without departing from the scope of the presently disclosed subject matter, mutatis mutandis. Examples of such armor are described, for example, in EP 2 023 072, and in PCT application PCT/EP10/058,520.

The ballistic structure 10 can be utilized as part of an add-on armor. As illustrated in FIG. 4, one or more add-on armor modules 30 can be mounted on a vehicle 32 to protect it from ballistic threats. The add-on armor modules 30, together with the sidewall of the vehicle to be protected thereby, are designed to defeat one or more known ballistic threats. Thus, when designing the add-on armor module 30, relevant parameters, including material, thickness, etc., of the sidewall of the vehicle are taken into account.

As illustrated in FIG. 5, the add-on armor module 30 comprises a ballistic structure 10 as described above with reference to FIGS. 1 through 3 within a casing 34. The casing 34 can be made of any suitable material, such as aluminum, fiberglass, or Kevlar. A fabric layer can be provided in front of the front pellet layer 12 a of the ballistic structure (henceforth referred to a front fabric layer 36), between the front and rear pellet layers 12 a, 12 b, and/or behind the rear pellet layer 12 b. The front fabric layer 36 can at least partially wrap around the other layers within the casing 34, e.g., extending along the sides of the structure and partially covering its rear. Binder matrix material can permeate at least some of the fabric layers. The fabric layers can be made of any suitable ballistic fabric, including, but not limited to, aramid, polyethylene, and fiberglass. In addition, a backing 44, e.g., made of fabric layers such as aramid, fiberglass or polyethylene, or of metal such as steel, aluminum, titanium, can be provided behind the pellet layers 12. A metal casing cover 37, for example made of the same material as is the casing 34, can be provided at the rear end of the add-on armor module 30. The metal casing cover 37 can be provided for constructional purposes (e.g., to keep the module planar) and/or to protect the module from adverse environmental conditions, and does not need to significantly contribute to the ballistic performance of the module 30.

It will be appreciated that the add-on armor module 30 as described above with reference to FIGS. 4 and 5 can be used in conjunction with an additional liner (not illustrated) attached to the inside of the vehicle directly behind the armor, in order to stop fragments and deformed projectiles from entering the vehicle.

It will be appreciated that in the accompanying figures, different layers are represented by different types of lines of varying thicknesses. However, the thicknesses of these lines do not necessarily correspond to the thicknesses of the layers which they represent. Thus, for example, several fabric layers can be represented in the accompanying figures by several spaced apart lines, which total thickness approaches that of the ballistic structure, which in reality the ballistic structure can be much thicker than the fabric layers.

Alternatively, the ballistic structure 10 as described above with reference to FIGS. 1 though 3 can be utilized as part of a standalone armor. As illustrated in FIG. 6, one or more standalone armor modules 38 can be mounted on a vehicle frame 40 to assemble a vehicle, designated by 42, protected from ballistic threats. The standalone armor modules 38 are designed to defeat one or more known ballistic threats.

As illustrated in FIGS. 7A through 7C, the standalone armor module 38 is designed similarly to the add-on armor module described above with reference to FIG. 5. In particular, it comprises a ballistic structure 10 as described above with reference to FIGS. 1 through 3 within a metal casing 34. The casing 34 can be made of any suitable material, such as aluminum. A front fabric layer 36 can be provided in front of the front pellet layer 12 a of the ballistic structure. In addition, a backing 44, which contribute to the overall ballistic performance of the standalone armor module 38, are provided behind the rear pellet layer 12 b.

Binder matrix material can permeate the backing 44. The fabric layers can be made of any suitable ballistic fabric, including, but not limited to, aramid, polyethylene, and fiberglass.

As illustrated in FIG. 7A, the backing 44 can be constituted by several fabric backing layers 46. The fabric backing layers 46 can be made of any suitable ballistic fabric, including, but not limited to, aramid, polyethylene, and fiberglass. As illustrated in FIG. 7B, the backing 44 can be constituted by one or more hard metal layers 48. The hard metal layers 48 can be made of aluminum, high-hardness steel, titanium, or any other suitable material. As illustrated in FIG. 7C, the backing 44 can be constituted by a combination of both the fabric and hard armor metal layers 46, 48. The number and/or thickness of the backing 44 is to be determined by the designer based on the ballistic requirements of the standalone armor module 38, such that the module can, by itself, defeat the ballistic threat for which it is designed.

As illustrated in FIG. 8A, both the add-on armor module 30 and standalone armor module 38 can be formed at one or more side edges 50 thereof with a projecting portion 52 disposed adjacent and level with one of the pellet layers 12 of the ballistic structure 10 within the module. (It will be appreciated that the representation of the ballistic structure in FIG. 8A is schematic, and that it may be provided according to any example of the presently disclosed subject matter, including, but not limited to, those described with reference to any one of FIGS. 5 and 7A through 7C.) The projecting portion 52 constitutes the top or bottom portion of the sidewall 50, being in fact a continuation of one of the layers 12 projecting past the other layer, in the plan view of the module. The projecting portions 52 allow several modules 30, 38 to be conveniently arranged side-by-side as illustrated in FIG. 8B to form an assembly 75, which can constitute at least a portion of a vehicle sidewall, and/or can allow modules to be replaced easily. It also ensures complete ballistic coverage in the area wherein adjacent modules 30, 38 border one another by providing for an overlap between front and rear pellet layers 12 a, 12 b of adjacent modules. It is formed so as to accommodate the ballistic structure 10 when formed with one of the pellet layers 12 projecting farther than the other at least one edge thereof, as illustrated in FIG. 8C. The projecting portion 52 can be made of incomplete pellets 56 having the same height as the pellets 14 of the layer of which it constitutes a continuation, in order to provide continuous coverage. The incomplete pellets 56 can be semi-circular, having a circular side facing adjacent pellets of the corresponding layer, and a straight side facing to the exterior of the layer.

The width W of the projecting portion 52 in the plan view of the structure 10 can be no less than about half the diameter of a pellet 14, e.g., when made of semi-circular pellets, and can be up to about three times the diameter of a pellet, although it can be even wider. In any event, the width W of the projecting portion 52 should be designed so as to support an arrangement of modules 30, 38 as illustrated in FIG. 8B.

Providing modules 30, 38 such as described above provides several advantages. For example, the armor assembly 75 can be assembled to any desired size from prefabricated parts. In addition, in the event that several pellets are damaged, e.g., due to impact of projectiles, the module containing the damaged pellets can be easily replaced, without having to replace the entire assembly.

The ballistic structure 10 can be used as part of a flexible body armor. As illustrated in FIG. 9, a body armor is designed to protect vital organs 58 of a wearer, and as such should cover at least the area indicated by 60. In addition, such an armor should maintain a degree of flexibility in order to accommodate changes in the shape of the torso of the wearer, for example due to crouching, to accommodate firing/shooting position of the wearer, and other movements of the wearer.

As illustrated in FIGS. 10A and 10B, a flexible body armor 62, e.g., for use in a personal bullet-proof vest, is provided comprising a flexible enclosure 64 containing therewithin ballistic structure 10 as described above with reference to FIGS. 1 through 3 and a fabric layer 66.

The flexible enclosure 64 can be formed as a sack of dimensions suitable to accommodate therewithin the ballistic structure 10 and fabric layer 66, as well as any other layers or elements which can be provided. It can be made of any suitable material which provides ballistic protection, such as aramid. Alternatively, it can be made of a material which offers no ballistic protection, such as polyester, cotton, etc. Appropriate accessories (not illustrated), such as snaps, buttons, straps, etc., can be provided in order to fasten, adjust, etc. the body armor 62 on the wearer.

The pellet layers 12 of the ballistic structure 10 can be free to change shapes relative to one another, e.g. when bended, without moving parallel to each other. Such an arrangement imparts flexibility to the layers.

This can be accomplished by providing them substantially free of bonds directly therebetween (they may, however, be attached along at least portions of their peripheries, and/or they can be both attached to a single element along at least a portion of their peripheries). Such an arrangement allows the pellet layers 12 to remain adjacent one another while remaining flexible. This can also be accomplished by attaching them together at select portions of their adjacent surfaces. For example, the pellet layers 12 can be connected to one another along a line running along a centerline thereof. Although the areas of the pellet layers 12 which are close to the point or area of attachment have limited movement with respect to one another, overall, the ballistic structure 10 can together retain a high degree of flexibility.

In addition, the binder matrix is made out of a flexible material.

As such, and as illustrated in FIG. 10A, the body armor 62 is configured to bend about several axes 68, which imparts an overall flexibility suitable therefor, as described above.

The fabric layer 66 can comprise a plurality of sub-layers 70 of ballistic fabric. The ballistic fabric can be aramid, polyethylene, fiberglass, or any other suitable material. The sub-layers 70 can be sewn together and un-pressed, in order to maintain a high degree of flexibility of the fabric layer 66.

According to a modification illustrated in FIGS. 10C and 10D, the body armor 62 can be provided with flexible hinges 65, for example if the binder matrix does not provide sufficient flexibility, for example along axis 67. FIG. 10C illustrates a pellet layer 12 with the footprints of hinges 65 attached thereto indicated by their outlines; the footprint of the hinge attached to the front side of the pellet layer (and its associated axis) being indicated by a solid line (and being slightly elongated for clarity), and the footprint of the hinge attached to the rear side of the pellet layer (and its associated axis) being indicated by a broken line.

The hinges 65 can be made of a flexible material, for example a fabric such as aramid or polyester, or an elastomer such as natural or artificial rubber, or of any other suitable material. The flexible material of the hinges can be more flexible than the binder matrix. According to the illustrated example, each hinge comprises a strip of material attached to ends of two adjacent rows of pellets 14. Such an arrangement can allow bending of the body armor 62 through an angle up to 180° (i.e., the final disposition of the two adjacent rows represents a rotation of 180° from the original, un-bended, disposition thereof). In the event, for example, that the hinges 65 are made out of an elastomeric material, the hinges can allow bending up to 180° in one direction, and somewhat in the other direction. The degree of bending allowed in the other direction depends on a several factors including, but not limited to, the material of the hinge 65 and the distance between adjacent pellets 14 in the pellet layer 12.

In order to facilitate bending of the ballistic structure 10, hinges 65 can be provided in corresponding rows in adjacent pellet layers 12, i.e., a hinge can be provided on rows of the rear pellet layer 12 b below those on which a hinge is provided on the front pellet layer 12 a, in order to allow both pellet layers to bend together, such as illustrated in FIG. 10D.

A single row of pellets 14 can be attached to a hinge 65 on its front and rear sides, with the front-facing hinge being attached to an adjacent row on one side thereof, and the rear-facing hinge being attached to an adjacent row on the other side thereof. It will be appreciated that the binder matrix between adjacent rows of pellet 14 attached to a single hinge 65 can be broken or weakened to allow for the bending.

The hinges 65 can be attached during formation of the pellet layers 12 or thereafter.

It will be appreciated that an armor similar in design to the body armor 62 can be provided in shapes which make it suitable for other uses, such as wrapping part of vehicles or articles to provide ballistic protection therefor.

The ballistic structure 10 can be manufactured as follows:

The pellets 14 are prepared by cleaning with a surface preparation chemical agent. They are then coated with one or more coats of primer, such as Silan, or any other suitable bonding agent. The coating can be accomplished by spraying the pellets 14 with the primer, or by immersion thereof in a bath of the primer. The spraying can be accomplished by standing the pellets 14 on their rear ends 18 b, spraying the primer thereon, and allowing them to dry. This coats all surfaces except the rear ends 18 b. When the pellets 14 are later arranged for production with their rear ends facing upward, as described below, the primer is applied to the rear ends 18 b, thereby ensuring that the entire surface of each pellets 14 is coated therewith. Alternatively, the entire surface of the pellets 14 can be coated prior to their arrangement for production. The primer can be applied manually or in an automated fashion.

A non-limiting description of a process which can be employed for manufacturing armor as above will be presented below with reference to FIGS. 11A through 11C.

As illustrated in FIG. 11A, a mold 72, which can be made of aluminum or other similar material, is provided, having dimensions corresponding to those of the armor module 30, 38 or body armor 62. A cover 74, associated with the mold, can be provided. It has dimensions which are slightly smaller than those defined by the interior of the mold 72. A front fabric layer 36 is optionally arranged in a generally horizontal position within the casing 34 and the mold 72, and the edges thereof are arranged along sidewalls thereof, defining a cavity 76. As seen in FIG. 11B, the pellets 14 are arranged within the cavity 76 in a honeycomb arrangement to form the front pellet layer 12 a. The sidewalls of the mold 72 are shifted until the pellets 14 are tightly packed. In the event that an armor module is being manufactured with a projecting portion 52 as described above with reference to FIGS. 8A through 8C, incomplete, e.g., semi-circular, pellets are provided as necessary. The pellets can be placed in the mold as part of a semi-fabricated layer, for example as disclosed in the Applicant's IL 182511.

Binder material in powder or liquid form is introduced in the mold 72 to fill the gaps between the pellets and fully cover them, including the planar rear ends 18 b thereof. The binder matrix is adapted to bind the pellets 14 to each other and to the adjacent layers.

As seen in FIG. 11C, the optional intermediate layer 13 can be applied to the rear ends 18 b of the pellets 14. In the event that the pellets 14 are formed with planar rear ends 18 b, and if the intermediate layer 13 is provided as a fabric layer, it can be easily and smoothly applied to the pellet array. This provides a better attachment of the intermediate layer 13 to the rear ends 18 b of the pellets 14, thereby increasing the confinement therebetween, which increases the ballistic protection.

Subsequently, the rear pellet layer 12 b is formed on top of the intermediate layer 13 (if no intermediate layer is provided, then the rear pellet layer is formed immediately on top of the front pellet layer 12 a). In the event that one or more fabric backing layers are provided, suitable ballistic fabric is provided on top of the rear pellet layer 12 b, similar to that described with reference to the intermediate fabric layer 13. If a backing 44 is provided, it is placed above the rear pellet layer 12 b.

Each of the fabric layers, if provided, can be pre-impregnated with the binder matrix.

As seen in FIG. 11C, if a front fabric layer 36 is provided, the edges thereof are wrapped around all of the layers above it. The casing cover 37 is placed on top. The cover 74 is placed at the rear. Heat and pressure are then applied by a press (not shown), which melt and press the powder, forming thereby the ballistic structure 10, along with any other layers provided therewith. The cover 74 can be used to distribute the pressure the pellets. Alternatively, the entire mold with the pellets can be covered with a plastic bag and placed inside an autoclave (not shown). In the event that the binder material is a thermoset, and was therefore introduced as a liquid, enough heat and pressure needs to be applied to cure the binder material.

The heating expands the mold 72, which allows the pellets 14, which heretofore have been held in contact with one another, to separate slightly by the binder material, whether a thermoplastic or thermoset, at this stage in liquid form, drawn by the primer in-between the pellets 14. When the binder material solidifies, there is produced a gap of 0.1 and 0.3 mm between adjacent pellets 14 at their closest points. This gap contains the primer and the binder material. The presence of the binder between adjacent pellets 14 improves ballistic protection of the armor by reducing propagation of shockwaves through the armor upon impact by a projectile and lessening the effect of shattering pellets on those adjacent thereto.

It will be appreciated that the method of manufacture described above with reference to FIGS. 11A through 11C can be modified when producing the ballistic structure 10 for use as part of a personal armor 62, for example as follows:

-   -   Only the layers 12 of the ballistic structure 10 are         manufactured as described above. The fabric layers 66 of the         personal armor 62 are added later.     -   After pellets 14 are arranged within the mold 72 to form the         front pellet layer 12 a, the binder material is introduced, then         a plastic separation layer (not illustrated) is placed thereupon         before pellets are arranged thereabove to form the rear pellet         layer 12 b. The plastic separation layer serves to maintain the         front and rear pellet layers 12 a, 12 b separate from each         other. Binder material is then applied to the rear pellet layer         12 b, and the cover 74 is placed thereupon.

The processes described above can be modified by manufacturing each pellet layer 12 separately. 

1. A ballistic structure, comprising: a front pellet layer configured to face a ballistic threat; and a rear pellet layer positioned behind the front pellet layer, each of the front and rear pellet layers comprising a plurality of pellets having cylindrical bodies with their height axes in both of the front and rear pellet layers being substantially parallel to each other, the plurality of pellets being arranged in a honeycomb pattern within a binder matrix, the front and rear pellet layers being codisposed such that all interior spaces of each of the front and rear pellet layers are entirely overlapped by an area of the other pellet layer that is free of the interior spaces, the front and rear pellet layers being spaced by an intermediate layer having a width and being made of a material so as to allow the rear pellet layer to rigidly support the front pellet layer.
 2. The ballistic structure according to claim 1, wherein some of the plurality of pellets in each of the front and rear pellet layers are in contact with adjacent ones of the plurality of pellets of the same layer.
 3. The ballistic structure according to claim 1, wherein the intermediate layer is configured to provide structural confinement to the front and rear pellet layers.
 4. The ballistic structure according to claim 1, wherein the front and rear pellet layers and the intermediate layer are within a single binder matrix.
 5. The ballistic structure according to claim 1, wherein each of the front and rear pellet layers are within a binder matrix separate from that which the other of the layers is within.
 6. The ballistic structure according to claim 1, wherein the plurality of pellets are made from a ceramic material.
 7. The ballistic structure according to claim 1, wherein centers of pellets in each of the front and rear pellet layers overlap with points of contacts of pellets in the other of the pellet layers.
 8. The ballistic structure according to claim 1, wherein each of the front and rear pellet layers is offset, relative to the other of the front and rear pellet layers, along a row thereof by a distance substantially equal to one half of the diameter of one of the plurality of pellets.
 9. The ballistic structure according to claim 1, wherein the intermediate layer is made of ballistic fabric or metal or the material of the binder matrix.
 10. The ballistic structure according to claim 1, wherein the plurality of pellets are made of a transparent material.
 11. The ballistic structure according to claim 10, wherein the binder matrix is made of a transparent material.
 12. An armor module comprising the ballistic structure according to claim 1, and further comprising a casing enclosing the ballistic structure at least along sidewalls thereof extending between external surfaces of the armor module that are substantially parallel to the front and rear pellet layers.
 13. The armor module according to claim 12, further comprising at least one backing layer.
 14. An armor assembly comprising a plurality of the armor modules according to claim 12, wherein the plurality of the armor modules are arranged such that projecting portions of adjacent ones of the plurality of the armor modules overlap one another.
 15. A vehicle comprising a plurality of the armor modules according to claim
 12. 16. A vehicle comprising one or more of the ballistic structures according claim
 1. 17. A vehicle comprising the armor assembly according to claim
 14. 18. A method for producing the ballistic structure according to claim 1, the method comprising: providing a front fabric layer and plurality of pellets; arranging the front fabric layer in the form of a cavity having a generally horizontal bottom and generally vertical side walls; arranging some of the plurality of pellets in the cavity on the generally horizontal bottom to form a front pellet layer; arranging other of the plurality of pellets on top of the front pellet layer to form a rear pellet layer; and applying binder material to the plurality of pellets and the fabric layers in such a way so as to substantially simultaneously form a matrix, which constitutes with the plurality of pellets the ballistic structure, and to bind the front layer thereto.
 19. The method according to claim 18, wherein the matrix is formed by heating and/or applying pressure to the binder matrix.
 20. The method according to claim 18, further comprising introducing an intermediate layer between at least a portion of the front and rear pellet layers. 